Theoretically it should be possible, depending on what mods you use. I've been using Kanan so I'm not exactly sure the current status of data folder injection with other mods, but if the other mods work then I'm sure it's be possible, just a little research may be needed. All that you would need to do for Kanan is copy the data files specifically into the data folder inside Kanan, but do not modify the base Mabinogi folder. That would result in quite a bit of trouble (for instance, having to reinstall Mabinogi or revert to a backup folder, which I will always suggest having on standby). If the maps don't load, you may need to modify the data folder loading script or activate it. Some of the scripts have been found to not work recently but my data folder script seems to be running fine. If it doesn't work, simply wait for an update to go live and I'm sure it will be possible.